BAGRAM AIR FIELD, Afghanistan - In an attempt to steal the spotlight from Afghan President Hamid Karzai's trip to Washington, the Taliban threatened to launch a series of attacks across Afghanistan -- a claim the defence minister quickly dismissed as insurgent propaganda.

The Taliban said their spring offensive, targeting Afghan and NATO military and staff plus foreign contractors, would begin on Monday -- the same day that Karzai begins meetings in Washington. A statement in English posted Saturday on the group's website said the offensive dubbed "al-Faath," which means victory, will include "ambushes, detonations of explosive devices, assassinations of government officials, suicide bombings and detainment of foreign invaders."

Defence Minister Gen. Abdul Rahim Wardak dismissed the threat, saying that the Taliban did not have the capability to launch a series of attacks across the nation. Moreover, he said, intelligence reports show many of the Taliban commanders currently are across the border in Pakistan.

"I do believe it is a propaganda campaign rather than a reality," Wardak said.

Wardak and nine other members of the Afghan Cabinet are accompanying Karzai to the United States. The trip comes as 30,000 U.S. reinforcements President Barack Obama dispatched to the war head to the country. About 4,500 have deployed, with another 18,000 due to arrive by late spring and the rest by early fall.

The military buildup is aimed at routing the Taliban from their strongholds, especially in the south, and bolstering security needed to start development projects and offer public services -- an effort to drain support for the Taliban and throw it to Karzai's government.

Thousands of U.S., NATO and Afghan forces just finished a major offensive to oust the Taliban from central Helmand province in the south. They now are ramping up pressure on the Taliban's birthplace of Kandahar province next door.

The Taliban are fighting back with attacks on contractors and government officials. A Taliban spokesman claimed responsibility for killing Manan Khan and two of his body guards on Saturday. Khan was a former police chief and current vice-president of the shura, or council, in Arghandab district, a dangerous area of Kandahar. Last month, gunmen stormed a mosque and killed the deputy mayor of Kandahar as he knelt for evening prayers.

In a recent commentary, Karzai appeared to highlight the role the militants in Pakistan play in Afghanistan. Kabul accuses Pakistan of harbouring militants who launch attacks across the border into Afghanistan.

"We have travelled far together, but the international effort in Afghanistan still has miles to go," Karzai wrote in an opinion piece published Saturday in The Washington Post. "We are not yet delivering security to large portions of the country. I have consistently noted the urgency of addressing the problem of sanctuaries, training and other support that terrorists receive beyond Afghanistan's borders. This problem is far from solved."

Karzai highlighted positive aspects of U.S.-Afghan relations, but also called for an end to night raids and house searches and stepped up efforts to curb the deaths of Afghans caught in the crossfire. "Civilian casualties are harming our cause," he wrote. Top NATO Commander Gen. Stanley McChrystal's leadership "has done a lot to address this, but more needs to be done."

Earlier this year, McChrystal issued a new directive ordering coalition forces to avoid night raids when possible, and bring Afghan troops with them if they must enter homes after dark.